I'm talking about Illasera, Gromnir, Yaga-Shura and Abazigal. I'd like to know which version is tougher. I've already played Ascension several times, but it's first time I've installed IA. I'm unsure.
Oh, and the same question about Sendai and her Oversight version.

PS Does IA affect Demogorgon?

Can only speak for IA 3, but in that version gromnir was easier than david gaider's envisioning and yaga-shura was harder.

Improved Illasera is much tougher than the one of Ascension.
Gromnir maybe a bit more difficult but not by much.

Yagashura,Abazigal and Sendai are also tougher but since I have faced them only once I can't be very objective. After some times and with new tactics every battle becomes easier.

About Demogorgon I think Sikret plans to make an improved version for the 5th version of IA.
But there is a battle in the W.Keep that is much more difficult than Ascension's Demogorgon

The point is that if you intend to install and play Improved Anvil, you cannot install any of Ascension's components except the "core" component and the "Improved Demogorgon". Every other component of Ascension are simply incompatible. So, you don't have a choice here. Even the "core" component of Ascension is compatible with IA if and only if you install it before Improved Anvil.

Heh, I didn't say I was going to replace IA's components with Asc's ones. That would be unfair - to kill IA's stuff without even trying it.


Any special reason or just for safety?

I suppose that the reason is that Ascension adds more content instead of only harder battles and if you install it before IA, IA overwrittes Ascension tougher final battle but you can keep the new content. If you install Ascension after IA, you will not play IA version of the battles.

AFAIK Ascension is a mod wich should go first in installation (After Baldurdash/BG2Fixpack)

If you install Ascension after IA, it will break IA's "Epic Divine Encounter" component completely. So, there is a very definite and strong reason for not installing Ascension after IA (in addition to the general reason Magnus mentioned).

Understood, thanks.